If I'd make a PCB to emulate the Dim(ention) D, are you confident you can get the required chips (MN3007, MN3101, NE571 or equiv., 2x each)?

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

The Dimension D board art is recoverable from the service manual documents. Or is it two-sided? I can't remember.

What I worry about, is that the transistors listed there do not have a single suffix, while the SH synths, TR808, etc. are -filled- with transistors of a highly specific nature- the 2SC945Q in the SH5 filter, the 2SC945P in the TR808... Has anyone taken a very good look at what is actually stuffed on the board?

Can you come up with a PCB that is smaller than the original? I'd definitely get one (already have the 3007s/3101s). Don't use the noisy chips..please.

Know that the Dimension D will add just the right amount of life to drum machine hihats, and is luscious on ballad guitars.

Yes, absolutely.
I'm aiming at a board in my "standard" size (160mm * 100mm).
I'll probably place the two BBDs in opposite corners to keep them away from each other.
I'll omit the line driver / balanced input & output stuff unless all of you convince me you need it. Driving 600 Ohm loads is the exception nowadays, I think. I'll leave it 2 channel-in, 2 channel-out , of course.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

Love it - still use it every day. When I run my CS-80 thru it, and then switch back to Dry, the CS-80 suddenly sounds weak. (Blasphemy, I know. )

It's not that almost static effect that the Dim D is, though. So I'm not entirely sure if there will be enough demand for it to make a full PCB run.

Right now, my Dim T consists of two partly populated Tau boards and a veroboard. It will be possible to build a similar configuration with one partly populated Dim D board (no BBDs then, of course) and two Tau boards, plus a little cross-wiring.
But my goal is to really make a Dim T on a board of its own. I just have to see if it'll work from an economic point of view.

Jh._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

I'm still not sure whether I should do it or not.
At the moment I'm just making preparation in order to be able to go when I'll get into the "Dim D mood" again.

I have to be in a certain mood, or state of high motivation, to do a specific project - then I can fly, and everything works almost on autopilot.
I've been in that mood for the Dim D some time ago, but I had promised barclaycon to wait until June, and so I put my focus on the Dim T idea, and then on the String Filter and Interpolating Scanner.
It's almost June, that other project on prodigy-pro seems uncertain, and I don't even know what to make of the reaction I got there recently.

Right now, I'm not in the Dim D mood - but I want to be ready to fly when it comes again. So I'm doing the preparatory homework right now.

Scott - what's the current state of your Dim C project?
Let me know if the situation for a Dim D is different than it was in January.
Do you still think it makes sense?

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

Not anymore.
(Been working part time - 4 days a week - for 2 months now.)

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

Doing a search gets you to it most easily. (They have it posted in the "transistor" section.)

Thanks Mike!

It could be a good idea to shop for these chips now.
I expect a similar situation as with the TDA1022's and the Triple Chorus (where in the end it turned out there _were_ enough chips, despite our initial fears), but you can never know.

The crucial chips are:

MN3007 (x2)
MN3101 (x2)
NE570 (x2) (or NE571, or SA570, or SA571)

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

The folks on prodigy-pro will be duking it out with us for components, so it might be a touch rougher than with the triple chorus. IMO, the "D" might be a bit more universally revered/known than the other excellent projects you've been producing...

Still waiting for my prodigy-pro account to be activated. Sigh. Well, if I can't post there, then E-M'ers get the first go at these cheap 3007s!

BTW, I would vote for a balanced I/O option- it's nice to be able to keep things clean when chaining pro gear. Would it be too clumsy to have the ability to stuff that, but to also use it with today's oscillator levels? Yikes.

What I worry about, is that the transistors listed there do not have a single suffix, while the SH synths, TR808, etc. are -filled- with transistors of a highly specific nature- the 2SC945Q in the SH5 filter, the 2SC945P in the TR808... Has anyone taken a very good look at what is actually stuffed on the board?

If I'd earlier taken a look at the left side of the schemo, I would have found those highly specific Japanese trannies- 2SC732TM-GR, 2SK30ATM-GR, 2SC945P, 2SA733P, etc.

XOX cloners argue over the hfe and vendor variance of these specific trannies regarding "does it sound right", are 4148s REALLY like 1S2473s, etc....Will more readily available Euro trannies be able to replace them? I'd trust you to be one of those who could do it, if you haven't already done so.

I would also vote for a balanced option, if possible. A unit like this, I'd most likely operate on a send/return path, rather than as a through effect.

Ok, I try to fit in balanced inputs/outputs.
But you don't need 600 Ohm drive capability, do you?

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

What I worry about, is that the transistors listed there do not have a single suffix, while the SH synths, TR808, etc. are -filled- with transistors of a highly specific nature- the 2SC945Q in the SH5 filter, the 2SC945P in the TR808... Has anyone taken a very good look at what is actually stuffed on the board?

If I'd earlier taken a look at the left side of the schemo, I would have found those highly specific Japanese trannies- 2SC732TM-GR, 2SK30ATM-GR, 2SC945P, 2SA733P, etc.

XOX cloners argue over the hfe and vendor variance of these specific trannies regarding "does it sound right", are 4148s REALLY like 1S2473s, etc....Will more readily available Euro trannies be able to replace them? I'd trust you to be one of those who could do it, if you haven't already done so.

I think sometimes these details can be important, and sometimes they don't matter at all. There is always the possibility to overlook something, of course. But I feel confident that I know the difference in most cases.
The emitter followers in the Dim D have 100% feedback per design - you won't notice any difference with about any small signal transistor.
(In my earlier Dimension Clone, I omitted them completely, btw.)
In a ladder filter, the transistor's parameters can make a substantial difference.
If a part with a certain suffix is specified in a service manual, this just specifies which part has been used. It means, the circuit will work if you use the same part - it doesn't mean it won't work with a part of a different suffix. It may not - but more often, it will. We have to find out.

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

I cast my vote for the MN3007s. I can get a fairly decent input level on my Dim C with its MN3207s, but, to be honest, in later dalliances with the MN30XX devices, I found them to be much less of a hassle to getting a good synth signal level. It still irketh me that the latter day MN devices are exclusively the MN32XX devices. Of course, I think JH could coax a fascinating signal out of an overripe cantaloupe if he put his considerable talents to it.

A while back (couple of years at least) I put some effort into making plans to do a Dim D, but I found the particular amplifier ICs used in the thing were really, really hard to find (some of the trannies as well). I bought one IC in order to compare it to other devices, but never got around to it (I'd gladly donate it to the cause if so needed). I've always suspected there were very suitable replacements today that the Roland guys didn't have around at the time they designed the Dim D. Any thoughts on what you're going to use there, JH?_________________My Site

It still irketh me that the latter day MN devices are exclusively the MN32XX devices.

They probably have a process that only allows small voltages?
Modern silicon technology goes for small structures (more circuits per waver), which also means less maximum voltage. High voltage processes are still there, but they are a speciality that you pay for, and not every manufacuter has them.

Quote:

A while back (couple of years at least) I put some effort into making plans to do a Dim D, but I found the particular amplifier ICs used in the thing were really, really hard to find (some of the trannies as well). I bought one IC in order to compare it to other devices, but never got around to it (I'd gladly donate it to the cause if so needed). I've always suspected there were very suitable replacements today that the Roland guys didn't have around at the time they designed the Dim D. Any thoughts on what you're going to use there, JH?

In my Dimension Clone from 2001 I used garden variety opamps, and never even thought about it. I still don't expect the opamp types -as long as the replacements are reasonably chosen - to make any difference here.
But I'll do two things:
(1) I'll check again if there's anything odd in the internal circuit of the opamps that were used in the original.
(2) I Consider providing SIL footprints and "ordinary" footprints on the board, so that he or she who thinks it might make a difference, can still hunt for the original opamps and solder them in.
(You could use sockets for the DIP parts, run the Dim D with them, and when you've found your holy grail, you can pull the DIP ICs and solder in the SIL parts.)
(3) If everyone has acess to "ordinary" SIL opamps (like the 4558, or the more common JFET opamps), I couls go straigt for SIL ...
(4) A combination of SIL and SOIC footprints might be an alternative as well.

JH.

PS.: Sorry for all the typos - gotta run ..._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

Boy did I speak too soon- eBay has gone nuts with cheap 3007s! There are tubes of 20 for $25.00, etc. Here's an example, $3.00 for two.

Good to see the good deals are still out there!

There has been a similar auction smome months ago (which also encouraged me to consider using 3007s rather than anything inferior.)

JH._________________"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f)

In my Dimension Clone from 2001 I used garden variety opamps, and never even thought about it. I still don't expect the opamp types -as long as the replacements are reasonably chosen - to make any difference here.

That makes sense to me. I wasn't really sure if those specific parts really had anything to do with anything - I'd say if the parts you chose in your clone worked out well, then that's that. I couldn't see anything paricularly special about those parts when comparing them to the plethora of op amps that are available these days.

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